But while scientists are certain that the Arctic is melting at an alarming rate, they aren't really sure why.

Although anthropogenic climate change accounts for some of the melting, Arctic ice is disappearing much faster than climate change models predict it should. A new study in Nature Climate Change sheds new light on the mystery.

AbstractThe Arctic has seen rapid sea-ice decline in the past three decades, whilst warming at about twice the global average rate. Yet the relationship between Arctic warming and sea-ice loss is not well understood. Here, we present evidence that trends in summertime atmospheric circulation may have contributed as much as 60% to the September sea-ice extent decline since 1979. A tendency towards a stronger anticyclonic circulation over Greenland and the Arctic Ocean with a barotropic structure in the troposphere increased the downwelling longwave radiation above the ice by warming and moistening the lower troposphere. Model experiments, with reanalysis data constraining atmospheric circulation, replicate the observed thermodynamic response and indicate that the near-surface changes are dominated by circulation changes rather than feedbacks from the changing sea-ice cover. Internal variability dominates the Arctic summer circulation trend and may be responsible for about 30–50% of the overall decline in September sea ice since 1979.

Popular Science quoted the lead author Qinghua Ding, a professor in the Geography Department at the University of California Santa Barbara.:

“There is a mismatch between the model's output and the observation. Observation shows very fast, very abrupt sea ice melting, whereas the climate model cannot capture the fast melting.”

"What we've found is that a good fraction of the decrease in September sea ice melt in the past several decades is most likely natural variability. That's not really a surprise," said co-author David Battisti, a UW professor of atmospheric sciences.

"The method is really innovative, and it nails down how much of the observed sea ice trend we've seen in recent decades in the Arctic is due to natural variability and how much is due to greenhouse gases."

Comments

This is an interesting spin on the issue.Climate “Science” on Trial; How Does Ice Melt In Sub-Zero Temperatures?https://co2islife.wordpress.com/2017/03/05/climate-science-on-trial-how-does-ice-melt-in-sub-zero-temperatures/

This has been written about for quite some time. Finally the "science" is catching up to reality.

This was predicted:Speak of the Devil; Nature Confirms the Arctic Sea Ice Atmospheric Circulation Theoryhttps://co2islife.wordpress.com/2017/03/26/speak-of-the-devil-nature-confirms-the-arctic-sea-ice-atmospheric-circulation-theory/

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This alarmist propaganda goes against the real data. Penn State Professor Michael Mann has made similar claims of modern temperatures being the warmest, but such “Hockey Stick” temperature claims have been demolished in the scientific literature.

Opinion by Anthony Cox
I wrote before about the ABC’s bias and the real
cost of the ABC to the Australian community. Since then the Abbott
government has announced reasonable budget cuts but the ABC has sunk further
into its betrayal of its Charter and of the Australian community.
In a recent poll about the farcical China/US deal about
emissions the ABC’s The Drum initially showed this result: 12/11/2014: China and the US have struck a new deal to limit greenhouse gas emissions. Do you think Australia will need to adjust its climate change policies as a result? No 55% Yes 44% Unsure 1%

15205 votes counted
Given the ABC’s Left/Green readership a remarkable result.
However shortly the result
was changed to this: 12/11/2014: China and the US have struck a new deal to limit greenhouse gas
emissions. Do you think Australia will need to adjust its climate change
policies as a result?Yes 76% No 23% Unsure 1% 6001
votes counted
How could you trust an organisation which lies like that and
distorts public …